Efficary of MRI for coevical caroid occlusive lesions : MR angiography and analysis of bool flow velocity using MRI

Magnetic resonance angiography (MRI) and analysis of blood flow velocity using MR imaging were performed on 45 patients with ischmeic cerebrovasxhlar diseases. The MRA, a conventional short-spin echo sequence with T_R 500 msec and T_E mesc, was able to show the running of the carotid bifhrcation as a low signal intense structure. Modified sagittal imaging obtained in parallel with the running of the common carotid artey was useful for visualization of the caroid bifurcation. The MRA findings were well correlated with those of conventional angiogram in 25 vessels among the patients. Blood flow velocity in the common carotid artey was measured by the direct bolus imaging (DBI) method, which was a new technique for visualizing moving fulid. DBI with electrocardiographic gating was able to show the pulsatile flow in the common carotid artey and to measure the blood flow velocity quantitatively. There was a significant discrepancy of blood flow velocity between patients with internal carotid occlusion and those without occlusive lesion. The results of analysis of flow velocity using the DBI method showed good reproducibility among any examiners. MRA and quantitative analysis of blood flow velocity using the DBI method were very useful for screening of patients with carotid arterial occulusive lesions. It is concluded that a conventional spin-echo sequence facilitates visualization of the carotid bifurcation, and that blood flow can be measured diagnostically using MRI.